JOURNAL OF MEMBRANE SCIENCE
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2019
·
IF 7.015
Tong Huang,Guangwei He,Jiandang Xue,Obed Otoo,Xueyi He,Haifei Jiang,Junfeng Zhang,Yan Yin,Zhongyi Jiang,John C. Douglin,Dario R. Dekel,Michael D. Guiver
Combining two facile methods, spinodal blending and self-crosslinking by chloromethyl groups are jointly utilized in fabricating alkaline anion exchange membranes (AEMs). Highly and moderately chloromethylated poly(ether ether ketone)s and sub-equimolar (to chloromethyl) amounts of 1-methylimidazole are mixed and reacted to form blend AEMs. Nanoscale bi-continuous phase separated morphologies are obtained due to spinodal decomposition. Subsequent heat treatment triggers self-crosslinking of the AEMs arising from residual chloromethyl groups in membranes. Compared with unblended and uncrosslinked AEMs having similar ion exchange capacity (IEC), the ion conductivity of the present AEMs is increased by 45.4% in water and 113% in 95% RH at 60 °C. Dimensional and alkaline stabilities of AEMs are also enhanced by the self-crosslinking, i.e., the swelling ratio decreases by 50.3% at 60 °C and the residual conductivity increases by 26.3% after alkaline treatment in 1 M NaOH at 60 °C. Interestingly, individual spinodal blending or self-crosslinking are found ineffective in overcoming the trade-off between AEM conductivity and stability, while a combination of both methods leads to a simultaneous improvement in conductivity and membrane stability.
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Catalysts
·
2019
·Vol. 9
·期 8
·632
·
IF 3.444
Kirill Alferov,Shuanjin Wang,Tianhao Li,Min Xiao,Shanyue Guan,Yuezhong Meng
Synthesis of copolymers from carbon dioxide (CO2) and epoxides is an important research direction as such processes utilize the abundant greenhouse gas and deliver useful products. Specifically, cooligomers of CO2and propylene oxide (PO) with a non-alternating structure can be used for polyurethane preparation. They are synthesized by employing Zn-Co cyanide catalysts. The application of alternative metal cyanide complexes is interesting from scientific and practical points of view. The purpose of this work was to study the copolymerization of CO2and PO in the presence of Co-Ni cyanide catalysts and chain transfer agents (CTAs) in order to obtain low molecular weight products. Three Co-Ni catalysts with different contents of complexing agents were synthesized, characterized by several analytical methods and applied for this reaction. The complex without complexing agents was chosen for detailed investigation. 1,6-Hexanediol proved to be a more preferred CTA than poly(propylene glycol) and adipic acid. An oligo(ethercarbonate) (Mn= 2560, PDI = 2.5, CO2= 20 mol.%) capped with OH groups was synthesized with relatively high productivity (1320 gPO+CO2/gcatin 24 h) and characterized by matrix-assisted laser desorption/ionization (MALDI) MS and NMR methods. The main chain transfer routes during the cooligomerization were suggested on the basis of the research results.Keywords:metal cyanide catalyst;cobalt;nickel;carbon dioxide;propylene oxide;copolymerization;chain transfer agent;oligo(ethercarbonate);polyurethanes
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JOURNAL OF ALLOYS AND COMPOUNDS
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2018
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IF 3.779
Junwei Yin,Zipeng Xing,Junyan Kuang,Zhenzi Li,Meng Li,Jiaojiao Jiang,Siyu Tan,Qi Zhu,Wei Zhou
Bi plasmon-enhanced mesoporous Bi 2 MoO 6 /Ti 3+ self-doped TiO 2 microsphere heterojunctions (Bi-BMO/TiO 2-x ) have been synthesized by a mild hydrothermal method combined with an in situ solid-state chemical reduction process, and subsequently annealed at 400 °C in N 2 atmosphere. The prepared Bi-BMO/TiO 2-x photocatalysts are characterized by X-ray diffraction, N 2 adsorption, scanning electron microscopy, transmission electron microscopy , and X-ray photoelectron spectroscopy. The results reveal that Ti 3+ self-doped TiO 2 is loaded on surface of mesoporous Bi 2 MoO 6 microsphere efficiently and metallic Bi is produced for surface plasmon resonance (SPR). Under visible-light irradiation, the heterojunctions photocatalyst shows excellent photodegradation and photoelectrochemical properties of ∼95% for phenol removal rate and 20 μA/cm 2 for photocurrent density, respectively, which is several times higher than that of single component. Moreover, it also has high photocatalytic oxygen production with a rate of 134 μmol h -1 g -1 . The enhanced photocatalytic activities are mainly attributed to the existence of Ti 3+ self-doping and heterojunction structure, which narrow the band gap to extend photoresponse to visible light region. Another reason is the influence of SPR of metallic Bi. They all promote the spatial separation and transfer of photogenerated charge carriers.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2018
·Vol. 411
·期 18
·4113-4121
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IF 3.307
Guo Chao,Guo Zhenpeng,Chen Yi
Capillary electrophoresis (CE) is excellent at separating all the ions in a sample but is rarely used as a result of its detection issue and easy loss of very fast ions by common one-end injection methods. Herein we propose a newly developed method aimed at simultaneous determination of positive and negative ions with a home-made CE device, featuring bi-end injection and contactless conductivity detection at the middle. By simply using 2.5 M acetic acid as a running buffer, the method can separate 37 ions (3 inorganic anions, 8 inorganic cations, 10 biogenic amines, and 16 amino acids) per run, with linearity between 10 and 2000 μM ( R 2 > 0.99), limit of detection of 1.0–16.6 μM, and limit of quantification of 2.3–31.7 μM. The recovery measured by spiking standards into samples at high, middle, and low levels was between 73% and 110%. The intra- and interday repeatability of the 37 analytes ranged from 0.69% to 8.97% and from 0.68% to 11.04%, respectively. The proposed method was evaluated by analysis of 21 beers and, in addition to acquiring the concentration information, the brands of the tested beers were distinguished. This method is of high throughput, fast, and cost-effective. It could be a promising tool for ionomic analysis.
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DALTON TRANSACTIONS
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2018
·Vol. 47
·期 46
·16696-16703
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IF 4.099
Lifei Xu,Yan Xu,Xianliang Li,Zhuopeng Wang,Ting Sun,Xia Zhang
The rational design strategy to construct lanthanide ion functionalized metal organic frameworks (MOFs) has attracted tremendous attention as they are promising candidates for developing novel luminescence materials and optical sensors owing to their intense, long-lived and tunable luminescence performances. In this work, a series of Eu3+/Tb3+ singly doped or codoped bismuth-based MOFs were prepared under in situ facile solvothermal conditions using BiOBr nanoplates as bismuth resources. A red-green-blue-based trichromatic white-light emission can be finely achieved by modulating the doping ratio of Eu3+/Tb3+ in the blue-emitting Bi-MOF host material and such photoluminescence tuning can also be realized by controlling the excitation wavelength. In addition, the Eu3+/Tb3+ singly incorporated Bi-MOF can serve as a multifunctional fluorescent probe for sensing Fe3+ and Cr2O72− ions in aqueous solution, as well as small organic pollutants of acetone molecules, and their sensing mechanisms have also been analyzed. These lanthanide ion functionalized Bi-MOF materials exhibit great potential in exploring white-light emitting devices and construction of supersensitive multifunctional sensors.
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Journal of Energy Chemistry
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2019
·
IF 5.162
Dan Liu,Gang Li,Hongchen Guo,Jiaxu Liu
Two kinds of bi-functional transition metal doped mesoporous materials (Fe-HMS and Fe-MCM-41) are prepared using one-step hydrothermal method and then treated with hydrochloric acid ethanol solution. The N 2 adsorption and HRTEM results show that both of Fe-HMS and Fe-MCM-41 possess mesoporous structure. The UV–vis results suggest that the Fe species are mainly located within the framework. The basicity of as-prepared samples was studied by temperature programmed desorption using CO 2 as probe molecule (CO 2 -TPD). The catalytic performance of Fe-HMS and Fe-MCM-41 in CO 2 cycloaddition largely depends on the amount of the accessible basic sites. The acid–base active sites, framework Fe and PDDA species cooperatively catalyze the CO 2 cycloaddition for the production of cyclic carbonates under the condition without any co-catalyst. The conversion of epichlorohydrin (ECH) is 97.4% and the selectivity of chloropropene carbonate is 92.9% under optimal conditions. The approximate rate constant of cycloaddition reaction of CO 2 with ECH under optimum reaction temperature is calculated. It is worth noting that the Fe-HMS material shows superior reusability than Fe-MCM-41. In addition, this work provides a facile way on the synthesis of bi-functional acid–base heterogeneous catalyst with outstanding catalytic performance for the fixation of CO 2 .
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CHINESE JOURNAL OF POLYMER SCIENCE
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2014
·Vol. 32
·期 5
·577-586
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IF 1.42
Chen Shu-fan,Sun Lian-lai,Luo Xuan,Jiang Xiao-dong,Wu Wei-dong,Fang Yu,Huang Chuan-qun,Yang Rui-zhuang,Zhang Qing-jun
Carbazole-based bi-functional photorefractive polyacrylates were prepared via free radical polymerization and post-azo-coupling reaction. The structure of polymers was characterized by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance ( 1 H-NMR) spectroscopy. The differential scanning calorimetry (DSC) and the thermal gravimetric analysis (TGA) were used to characterize the thermal property of polymers. The results indicate that though the glass transition temperature ( T
g ) of polymers increases with increasing the ratio of NLO groups, the polymers with different ratios of NLO groups still all show low glass transition temperatures around 60 °C, and good thermal stability, which are favorable to the practical application of these polymers. The gel permeation chromatographic (GPC) result indicates that these polymers all have high-molecular-weight which is favorable to the long term stability of the material. Further, these polymers have good solubility in chloroform solvent, and the solutions can easily be fabricated into optically transparent films. Gain coefficients of 75 cm −1 , 185 cm −1 and 66 cm −1 can be observed at zero external electric field without any addition agent or pre-poling for polymers P-2, P-3 and P-4 respectively. The different contents of NLO groups result in the different properties of polymers P-2, P-3 and P-4.
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OPTIK
·
2015
·
IF 0.677
Xijia He,Xuhui Xu,Cuiqiong Yan,Jianbei Qiu
Bi-doped zinic silicate glasses (SG) and germanate glasses (GG) were prepared and the relationship between Bi near infrared (NIR) luminescence and the glass structures were investigated. The absorption, visible luminescence, and X-ray photoelectron spectroscopy (XPS) spectra revealed that the lower valence state of Bi ions containing NIR active centers increased with the decrease of optical basicity in the two sets of glasses. However, the NIR emission in these glasses cannot be merely explained by the theory of optical basicity. In the SG glasses, there is no obvious structural change, the NIR luminescence can be well interpreted by theory of optical basicity. But there is a distinct transformation in the GG glasses, the abnormal fluorescence phenomenon can be connected with the local structure regulating effect. The mechanisms of the NIR emission and local structure regulating effect were discussed.
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JOURNAL OF NANOPARTICLE RESEARCH
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2016
·Vol. 18
·期 1
·1-13
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IF 2.101
Ma Shuzhen,Cai Qian,Lu Kailing,Liao Fan,Shao Mingwang
Abstract The bi-functional Au/FeS (Au/Co 3 O 4 ) composite was fabricated by in situ reducing Au nanoparticles onto the surface of FeS (Co 3 O 4 ). The as-prepared FeS possessed a multi-structure composed of plenty of nanoplates, which were coated by Au nanoparticles with an average size of ~47.5 nm. While the Co 3 O 4 showed a thin hexagonal sheet containing Au nanoparticles on its surface with an average size of ~79.0 nm. Both the as-prepared Au/FeS and Au/Co 3 O 4 composites exhibited excellent SERS performance, capable of enhancing the Raman signals of R6G molecules with the enhancement factor up to 1.81 × 10 6 and 7.60 × 10 4 , respectively. Moreover, Au/FeS (Au/Co 3 O 4 ) composite also has been verified to have intrinsic peroxidase-like activity, which could decompose H 2 O 2 into hydroxyl radicals and then degrade organic pollutants into small molecules. Therefore, SERS can be used to real-time and in situ monitoring the degradation process of R6G molecules, employing the Au/FeS (Au/Co 3 O 4 ) composite both as SERS substrate and catalyst. Graphical abstract SERS was used to real-time and in situ monitoring the degradation of R6G, employing the Au/FeS and Au/Co 3 O 4 composites both as SERS substrates and catalysts.
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JOURNAL OF APPLIED PHYSICS
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2017
·Vol. 121
·期 12
·
IF 2.068
Wu Lei,Dai LiDong,Li HePing,Hu Haiying,Zhuang YuKai,Liu KaiXiang
We present a pressure-induced amorphization for pure and 0.5 mol. % Bi 3+ -doped Zn 2 GeO 4 samples, measured by high pressure Raman spectroscopy and high resolution transmission electron microscopy. Pressure-induced conductivity switching phenomena were discovered for both samples at around ∼7.01 GPa and ∼11.11 GPa, respectively, which closely correlated with the crystalline-to-amorphous transformation. The detailed conduction mechanism and the defect reaction process at high pressure indicate that the application of pressure could efficiently manipulate the microstructure and electrical performance of rare-earth doped polycrystalline materials, and therefore holds great promise for numerous applications in the future.
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JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Jia Huang,Yunjie Zou,Lan Ling
Perfluorooctanoic acid (PFOA) is detected widely in surface and groundwater globally. Its removal poses a significant challenge due to its high chemical stability. This study demonstrates efficient PFOA degradation using poly-triazine-imides-tailored defective Bi 5 O 7 I (PTI/BB). Under 300 W Xe irradiation, 1 µg·L −1 PFOA could be degraded to 9.86 ng·L −1 after 3 h in the presence of 0.5 g·L −1 25 % PTI/BB. The mechanism investigation reveals that the oxygen vacancy (OV) in partially reduced Bi/Bi 5 O 7 I (BB) generates impurity states, enhancing the light-harvesting capacity. Furthermore, forming a type Ⅱ heterojunction between conjugated PTI and BB facilitates the efficient separation of photogenerated carriers. The resulting photogenerated electrons (reduction) and holes (oxidation) drive hydrogenation reduction and oxidative decarboxylation of PFOA, respectively. This synergistic effect consequently achieves significant defluorination of PFOA. The proposed PFOA degradation pathway via the PTI/BB catalyst offers new insights into the catalyst design for photocatalytic degradation of per- and polyfluoroalkyl substances (PFAS).
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JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
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2024
·
IF 4.3
Panpan Xu,Congli Guo,Wentao Hao,Li Sun,Ensi Cao
The internal barrier layer capacitance effect substantially contributes to the colossal permittivity in In and Nb co-doped TiO 2 (INTO) ceramics. Therefore, enhancing grain boundary density and ceramic compactness can efficaciously reduce their low-frequency dielectric loss . In this investigation, Bi 2 O 3 addition was utilized to aid sintering and refine grains for INTO ceramics. The results reveal that Bi-doped INTO ceramics, in contrast to their undoped counterparts, exhibit a more refined and compact grain structure with a significant increase in the quantity of grain boundaries. Moreover, a noticeable reduction in low-frequency dielectric loss from above 0.1 to below 0.05 and enhanced frequency stability of permittivity from below 10 Hz to approximately 10 kHz were observed, along with a decrease in the sintering temperature to 1300 °C. In comparison to undoped INTO ceramics, Bi doping also enhances the withstand voltage capability by a factor of 1.5–4 for Bi-doped INTO ceramics. However, as the sintering temperature of Bi-doped INTO ceramics increases and the grain size enlarges, their breakdown voltage gradually decreases, but the non-linear coefficient of current-voltage characteristics progressively increases. Analysis of complex impedance spectra confirms that the increased grain boundary density and resistance in Bi-doped INTO ceramics is the primary factor for the enhanced dielectric properties and withstand voltage capability.
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